If you go out to the fields at night in spring or summer, you can hear frogs singing __ (joy) here and there. It seems as if they were performing a field symphony.
The frog is a good and useful creature that benefits human beings. They can catch fast-moving insects. Each frog eats a large number of pests that are harmful ___ crops. This little creature is regarded ___ “the natural enemy of pests”．
_ now frogs are getting fewer and fewer. This is because they are killed and put on the table as a delicious dish by their chief enemy, human beings. It is ____ shameless and cruel act, isn’ t it？__ cause responsible for the rapid reduction of frogs is that farmers use insecticides (杀虫剂) to kill pests and frogs get killed as a result of drinking poisoned water ___ eating poison-killed insects.
Something must be done without delay __(save) frogs. If we don’t punish those ___ sell and kill frogs to make money, then one day all of us ____(punish) by nature for failing to keep the balance of nature.